Video images are generally represented by video signals produced in a raster scan. In such a raster scan, a horizontal sync pulse is produced at the beginning of the video signals representing each horizontal line. A vertical sync pulse is also produced at the end of the video signals representing a complete image. When the vertical sync pulse is produced, there is a relatively long blanking period during which the beam producing the image is returned from the lower right corner of the screen to the upper left corner of the screen so that a new raster scan can be initiated. During this blanking period, serration and equalization pulses are produced periodically to define successive intervals in the vertical blanking period.
One purpose of the sync pulse defining the beginning of each horizontal line is to insure that the beginning of each horizontal line occurs on a regulated basis such that the beginning of the successive horizontal line will define a straight vertical line. This assures that the image will be displayed on the screen without any distortion. To accomplish this, the rate of production of the horizontal sync pulses in the video signal is regulated. However, the serration and equalization pulses interfere with this regulation and adversely affect the time for the production of the sync pulses. This prevents the image displayed on the video screen from being as precise as might otherwise be desired. The problems described in this paragraph have existed for a long period of time without correction in spite of full knowledge in the industry of the existence of this problem over such period of time and consideration over this period of time of how to resolve the problem.